Flat bed web press index and registration

ABSTRACT

Index and registration means for a continuous web printing apparatus having a web indexing apparatus to create index indicia at predetermined intervals along the web and web index register means at each printing station adapted to cooperate with the index indicia to cause momentary registry of the web with each printing unit for accurate printing. Specifically, the web indexing means punches holes in the web and the web index register means at each printing station includes a shiftable projection reciprocally movable toward the web holes to interengage the holes thereby holding the web in position at each printing station.

United States Patent Black [451 Mar. 21, 1972 541 FLAT BED WEB PRESSINDEX AND 2,369,290 2 1945 Foard ..101/115 REGISTRATION 3,102,472 9/1963Kieckhefer ..101/228 3,221,646 12/1965 Hardy et a1. ..10l/l15 Inventor:James A- Black, Sparta, Kent 3 Berk ct u 49330 3,355,166 11/1967 Plumb....226/95 x [22] Fil d; Se t, 24, 1969 3,460,470 8/1969 Green et al...10l/115 1 pp 8 0,720 FOREIGN PATENTS OR APPLICATIONS Related US.Application Data 1,258,815 3/1961 France ..101/1 15 [62] gig/$91022?Ser. No. 617,885, Feb. 23, 1967, Pat. No. Primary Examiner clyde Icoughenour Attorney-Huizenga & Cooper Price, Heneveld [52] US. Cl..ll/ll5, 101/228, 226/57,

226/146 [57] ABSTRACT [51] Int. Cl. ..B41f 15/04, B4lf 15/10 I d dregistration means for a continuous web printing [58] Field of Search101/ 1 15, 121, 196, 228; apparatus having a web indexing apparatus tocreate index 226/56 147 dicia at predetermined intervals along the weband web index register means at each printing station adapted tocooperate 6] References cued with the index indicia to cause momentaryregistry of the web UNITED STATES PATENTS with each printing unit foraccurate printing. Specifically, the web indexing means punches holes 1nthe web and the web 1,677,472 7/ 1928 Fuchs 101/152 index register mea sat each printing station includes a shifta- 950,754 3/1910 bleprojection reciprocally movable toward the web holes to 1,637,658 8/1927Rose ..226/57 interengage th hol thereby holding the web in position at2,017,459 /1935 Howe et a1 101/115 each priming station 2,239,619 4/1941Murgatroyd et al. 101/115 2,359,825 10/1944 Campbell 101/1 2 Claims, 17Drawing Figures U |l!'- I Imp/9a 7 l I 1 F. F n '1 1- L 7 w? l PMENPEHMR21 m2 sum 2 or 8 INVENTOR. Mme! ,4 504.4% BY W PATENTEUMARZI 19723,650,207

sum 3 OF 8 INVEN'IOR. wv/W J ,4. mar

BY W

PAIENTEUMAHZI 1972 PAIENIEUMARZI 1972 3, 650,207

sum 5 or 8 PATENTEDMARZI I972 3,650,207

sum 7 OF 8 INVENTOR. 1/4Mf6' 4. 6/466 w g W FLAT BED WEB PRESS INDEX ANDREGISTRATION This is a divisional application of parent application Ser.No. 617,885, filed Feb. 23, 1967 now U.S. Pat. No. 3,499,233, andentitled Flat Bed Web Press.

This invention relates to a screen printing apparatus and method, andmore particularly to a web press apparatus capable of continuousmulticolor silk screen printing on a continuous web.

Silk screen printing is relatively complex and expensive in comparisonto other printing methods. Still, it is used extensively because of itscapacity to produce very high quality prints, and its capacity toaccommodate materials and goods in a manner not possible or practicalwith other printing techniques and apparatus.

One of the greatest contributory expense factors of silk screen printingresults from the present necessity of first printing and then dryingeach sheet item one at a time. This requires a substantial amount ofequipment and labor. Since the ink is usually of substantial thickness,large recirculatory dryers are normally employed to handle the separatedsheets. If a sheet is to contain more than one color ink, the processbecomes very involved since each sheet must be printed with one color ata time, fully dried in a dryer, and then reprinted and redried for eachadditional color. Moreover, maintaining proper registry of each sheetwith each succeeding ink pattern to be printed is extremely difficult,but must be maintained very accurately if acceptable products are toresult. As a practical matter, the expense mounts very considerably witheach additional color added. Hence, the product is apt to be veryexpensive unless the number of colors is limited to one or two.

It is a primary object of this invention therefor to provide a novelscreen printing apparatus and method enabling automatic, high qualitymulticolor screen printing.

Another object of this invention is to provide a screen printingapparatus capable of printing several different selected colors inpreselected overlapping patterns on individual portions of web stock,while maintaining completely accurate registry of each individual sheetportion with each color, automatically so that only a fraction of thetime, expense, and equipment is required compared to that normallyrequired.

Another object of this invention is to provide a novel screen printingapparatus capable of printing on a continuous web of stock.

Another object of this invention is to provide screen printing apparatuscapable of accurately printing several colors in preselected patterns ona continuous web of stock, and to do so in a fraction of the time and ata fraction of the expense of known multicolor screen printing equipmentand techniques.

Another object of this invention is to provide apparatus capable ofsuccessively printing and drying individual colors on a continuous webof stock on a rapid continuous basis, with the number of differentcolors being practically unlimited. The number and selection ofdifferent colors can be varied widely merely by using or passingsuccessive modules of combination printing and drying units.

Another object of this invention is to provide a novel mulitcolorcontinuous web screen printing apparatus having several print stationsoperating simultaneously on the web, and having exactly controlled,automatically regulated registry of each segment of the continuous webwith each successive print station.

Another object of this invention is to provide a novel screen printingapparatus having a plurality of printer units, wherein each printer unithas complete registry control of the particular web portion beingprinted by it.

Another object of this invention is to provide a novel continuous webscreen printing apparatus wherein each printer unit controls the feedrate of the web stock portion through and from the dryer unitimmediately upstream of the printer unit, so that a series of theprinter units can be in operation simultaneously.

Another object of this invention is to provide a continuous web screenprinting apparatus having dryer units capable of rapid drying andcontrolled positioning of a continuous web in the dryer, usingdynamically flowing drying air, while enabling the printing unitimmediately downstream thereof to intermittently draw web portionstherefrom without creating significant tension on the web.

Another object of this invention is to provide a novel screen printingunit particularly suited to handle continuous web stock in an accuratelycontrolled reliable fashion, to print selected colors in repeat patternson successive portions of the web, using a unique reciprocable bed thatsimultaneously accurately registers and advances stock, and alsosupports and retains the stock in registry during printing.

Another object of this invention is to provide a printing unit capableof repeat automatic operation on stock fed to it, and allowingsubstitution of squeegee elements in the printer unit withoutinterrupting the continuous flow of stock through the printer. Theprinter squeegee assembly is capable of being switched from one squeegeeto another in a fraction of a second, between pring strokes, so thatcontinuous web printing will not be interrupted or otherwise adverselyaffected. Moreover, the squeegee element in the squeegee assembly can beeasily replaced without stopping the printer.

Another object of this invention is to provide a novel screen printersqueegee assembly enabling change from one squeegee to another, merelyby rotating the assembly to disengage the one squeegee and operablyengage the other.

Another object of this invention is to provide a novel squeegee assemblydrive apparatus for a screen printing unit, enabling the squeegee tomake a print stroke transverse to a continuous web and then to allow theweb to advance the printed area through the station without beingadversely affected by the squeegee assembly.

Another object of this invention is to provide a novel, continuous feed,printed web dryer, employing dynamic air flow to cause rapid continuousdrying of the web and controlled positioning of the web as it isadvanced through the dryer.

Another object of this invention is to provide a novel continuous webdryer enabling the web to pass through a curvilinear non-wrinkling path,with its position being constantly controlled by the dynamic drying airitself. Moreover, the web positioning drying air has optimum sweepacross the printed surface for reliable rapid drying.

Another object of this invention is to provide a novel continuous webdryer enabling the web to be intermittently advanced therefrom andintermittently fed thereto by dynamic air flow caused by controlledpressure differential, without significant stress being applied to theweb.

These and other objects of this invention will become apparent uponstudying the following specification in conjunction with the drawings inwhich:

FIG. 1 is a side elevational view of the novel apparatus;

FIG. 2 is a plan view of the apparatus in FIG. 1;

FIG. 3 is a fragmentary perspective view of the registry punchingstation of the apparatus;

FIG. 4 is an enlarged elevational view of one of the printers in FIGS. 1and 2, taken on the plane IV-IV of FIG. 1;

FIG. 5 is a fragmentary elevational view of the apparatus in FIG. 4,viewed from the opposite side, i.e., taken on plane V- V of FIG. 1;

FIG. 6 is a fragmentary enlarged perspective view of the top portion ofthe apparatus in FIGS. 4 and 5;

FIG. 7 is an enlarged plan view of the apparatus in FIGS. 4 through 6;

FIG. 8 is a partial elevational view of the apparatus in FIG. 7, takenon plane VIIIVIII;

FIG. 9 is a fragmentary enlarged elevational, partially sectionally viewof the printing station in FIGS. 7 and 8, taken on plane IX-IX in FIG.7;

FIG. 10 is an enlarged fragmentary exploded view of an end portion ofthe novel squeegee apparatus in a printing station;

FIG. 11 is an elevational, partially sectional view of the apparatus inFIG. 10, as assembled;

FIG. 12 is an enlarged end elevational view of the squeegee apparatus inFIGS. 10 and l l, for the printing station;

FIG. 13 is a fragmentary plan view of the apparatus in FIG. 12;

FIG. 14 is a perspective view of one of the drying units in theequipment of FIGS. 1 and 2, shown with the front door open;

FIG. 15 is an end elevational view of the dryer unit in FIG. 14;

FIG. 16 is a front elevational view of the dryer unit in FIGS. 14 and15; and

FIG. 17 is a prospective view of a latch for locking the squeegeassembly in aligned position.

Referring to the drawings, the complete system 10 is composed of aseries of cooperative components including a web supply roll stocksupport means 12, web splicer means 14, slack container means 16, webpredryer means 18, web registry index punch means 20, a first printerand dryer combination including printing means 22 and dryer means 24, asecond printer and dryer combination including printer means 26 anddryer means 28, and optional units including slip coat applicator 30,laminator means 32, cross slitting means 34, longitudinal slitter means36, underscoring means 38, and cut off means 40.

As will be understood from the detailed description to follow, not onlyis the complete system unique, but also the web registry system, theindividual printing units, the squeegee assemblies on the printingunits, and the dryer assemblies. Two printer and dryer combinations areshown in the illustrative drawings. Actually, the number of printer anddryer combinations may be widely varied to suit a particularinstallation. Thus, instead of the two shown, a large number of four,eight, l0, more or less, can be employed merely by installing additionalcombinations in the sequence, or only one need be used. The numberemployed will depend upon the number of color variations to be obtained.In operation, the web actually is advanced from support means 12, pastsplicer 14 which is intended to splice the end of one roll with thebeginning of another, through temporary slack container 16, and throughpredryer 18 where initial excess moisture is removed. It then passesthrough registry index punch means which punches registry holes at acontrolled spacing along the web. Then, the web begins its passagethrough the selected number of printer and dryer combination series toapply the selected patterns in order to obtain the multicolor printstock. The printer units actually determine the rate of feed throughthis sequence. After printing, and the final drying step, the web maypass through the optional assemblies 30, 32, 34, 36, 38 and 40. The slipcoat applicator 30 can apply a protective coating, if desired, and/orlaminator means 32 can apply a protective cover sheet. The web can becross slit with means 34 and/or can be longitudinally slit with slitmeans 36 and/or can be underscored with means 38. It may then be cutinto individual sheets by reciprocating vertical cut off 40, or may berolled up in a roll, as desired.

It is believed that the entire system can be more readily understoodafter a detailed description of each of the components thereof. Hence,for convenience and clarity, the components will be described in theirsequential relationship.

WEB SUPPORT The web supply roll support means 12 basically includes apair of elongated support beams 50 and 52 (FIGS. 1 and 2), arrangedparallel to each other on a central transverse pivot shaft 54 mounted tosupport housing 56. Rotationally mounted between the opposite ends ofbeams 50 and 52 is a first roll 60 of web stock, removably mounted on acentral shaft, and a second roll 62 of web stock removably mounted onanother central shaft. The forward roll 60 supplies web stock until itis depleted, at which time the mechanism is rotated 180, end for end, tobring roll 62 from its inactive position as a spare to the activeposition for supplying web stock. This rotational action is obtained byrotating shaft 54 with a motor 66 through chain 68 and sprocket 70, thelatter being mounted on shaft 54. Thus, the system can be constantlysupplied with web stock W even though the individual rolls are depleted.It will be realized that when the exhausted roll is shifted to the spareposition, a new roll can be substituted therefor while the system isstill operating.

The web is positively advanced from the roll to predryer 18 inaccordance with demands of the system. Specifically, an advancing meanssuch as a pair of orificed, pulleymounted recirculating tapes 61 and 63(FIGS. 1 and 2) are advanced over the slotted upper surface of anevacuated table 65 to pull web W from the roll and advance it to slackcontrol container 16. The motor (not shown) driving tapes 61 and 63 isshut off and on in response to a limit switch 67 in container 16 so thata controlled amount of slack is maintained in the web ahead of predryer18.

SPLICER Immediately downstream of the web support means is splicer 14used to splice the tail end of one web with the new forward end ofanother web from the next roll, in order to provide a continuous web tothe system. The splicer may include suitable temporary holding meanssuch as a vacuum head 74 to hold and align the two ends of web as theyare spliced together by adhesion, taping, or the like. Normally, thissplicer is disengaged from the web stock, so that the web can constantlymove past it without interference from it.

PREDRYER Dryer assembly 18 is exactly like dryer assemblies 24 and 28which are employed in combination with printer units 22 and 26. Itsfunction is to remove any excess moisture which the web stock, usuallypaper, has taken on during storage and shipping. Its use is not alwaysnecessary, but is advisable in most instances to bring the moisturewithin a central range.

The dryer assembly 18, and hence dryer assembly 24 and 28,

has a construction illustrated most clearly in FIGS. 14 through 16. Ithas a cabinet housing which forms a specially configurated front chamberand an enclosed rear chamber 82 that communicates with an evacuatingmeans (not shown) through a passage outlet 84. The vacuum source may bea typical exhaust fan, with the amount of vacuum pull being variably byvarying out flow with an adjustable damper 84' in passage outlet 84. Thefront chamber is separated from the rear by a vertical partition 86.This front chamber has an open top and a curvilinear peripheral wall 88which defines a smooth curvilinear web path from its horizontal entryplane, through a convex shoulder, thence through a continuous concavebottom to reverse its direction from down to up, hence around anotherconvex shoulder to the horizontal exit plane. This curvature includes nosharp bends so that the web can be drawn through the generallybottle-shaped chamber in a smooth fashion by the printer unit downstreamof the dryer. The web is held against this periphery by air flow and bya pressure differential created across the web between the inner face ofthe web and the outer face adjacent the perforate surface 88. The webstock thus enters in the direction indicated by the arrow in FIG. 14,and exits also as indicated by the arrow. The dryer employs dynamic airflow for both web drying and web positioning. Heat is supplied to themoving air in the front chamber by suitable forwardly projectingelectrical heating elements such as Calrod units 94. A plurality (four)of protector rods 96 project forwardly at intervals around thesev heaterelements, spaced inwardly from the peripheral curvilinear guide wall toprevent the web from ever being brought into contact with he heaterelements should the web be accidentally drawn too tightly in the dryer.

The front chamber is normally closed by a hinged access door 98 whichswings between its open position shown in FIG. 14 to its closed positionshown in FIG. 15. The door is maintained in its closed relationship by aplurality of magnetic catches 99. This door preferably includes a glasswindow 100 for observation of the interior of the unit. On the insideface of the door is a protruding sealing gasket 102 which extends aroundthe entire periphery of the chamber. Gaskets also extend around a pairof air inlets 105 and 106 in the door, which communicate with acooperative set of air flow passages 108 and 110 respectively thatextend to rear chamber 82. Dynamic air flow through the front chamber iscaused by pulling a vacuum on the front chamber via the rear chamber andallowing air to flow in the open top of the chamber. MOre specifically,communication is achieved by a large number of small air flow orifices114 in partition 86, located in a pattern around the inner chamber,immediately adjacent the perforate curvilinear surface 88, and, oppositethese orifices, in the same pattern, another series of orifices 116 inthe front panel of hollow door 98 to provide communication between thiscurvilinear chamber and the interior of door 98. These orifices 116 arealso immediately adjacent the curvilinear surface 88 when the door isclosed. Negative air pressure is provided to the interior of door 98 bycommunication of orifices 104 and 106 from the door interior topassageways 108 and 110, and thus with rear chamber 82 that associateswith vacuum outlet 84. When vacuum is pulled on rear chamber 82, airflows continuously down through the open top of the front chamber andthrough the orifices 114 and 116, to the rear chamber 82 of the cabinet.

This continuous air flow into the front chamber is further directed byan inverted V-shaped air deflector guide 90 that causes the air todiverge after it passes through the narrow necked down portion where theweb enters and leaves, along the inner surface of the web. Thus, the airhas optimum flow across the surface of the web and out throughpassageways 114 on the lateral edges of the web. By causing this airflow to occur constantly along the length and across the width of theweb as the web passes through the dryer, an excellent rapid, easilycontrolled drying action occurs while the web is being advanced by theprinting unit downstream thereof. Further, the pressure differentialacross the web, between the incoming atmospheric pressure air and thenegative pressure pulled on the orifices and on the back of perforatesurface 88 maintains the web adjacent the curvilinear surface.

REGISTRY INDEX PUNCH For proper operation of the system, very accurateregistry must be obtained between each segment of the web to be printedand each successive printing unit. After considerable experimentation,the best and most dependable technique devised was found to-include thecontrol of the web with pins (at each printing station) that projectinto prepunched holes in the web at spaced intervals therealong. Theholes are punched by the unit (FIGS. 1,2 and 3).

This punch means includes a die holder and guide surface 130 over whichweb W passes and on which it temporarily stops at intervals betweenintermittent web advancement by the first printing unit 20. The holesare actually punched by a plurality of (three) punch elements 132mounted by supports 134 to a vertically reciprocating platen 136 whichis guided by column 138. Platen 136 is depressed by pivotal lever 140which is also connected to reciprocating link 142. Suitable power means(not shown) operates link 142. After the platen is depressed to lowerpunch elements 132 through orificed guide plate 144, the platen is thenbiased upwardly by a spring 146 beneath post 148 which is attached toplated 136. The holes are punched in the web after the web is drawn tautby the next printing unit 22 downstream thereof, so that the holes havea definite space relationship to the previously punched series of holesthat are at the first printing unit. Each printing unit holds the webtight by vacuum and a set of registry pins projecting into thepreviously punched holes of the previously advanced section of the webas explained hereinafter. Thus, the spacing between the punched holes isexact and controlled.

PRINTER AND DRYER COMBINATION As explained previously, the completesystem includes any selected number of printer and dryer combinations,with the illustrative apparatus showing two such combinations. Also, asnoted above, each of the dryer units of the printer and dryercombinations basically has a construction like that described withrespect to predryer 18. The printer units are also basically the same,except that each, in operation, normally includes a different removablesilk screen pattern, preselected to apply the particular color of ink atthe printing station in a predetermined pattern to the multicolorprinted web. Hence, printer unit 22 will be described, with it beingunderstood that unit 26 is basically the same.

The detailed construction of the printer assembly is best illustrated inFIGS. 5 through 13. Printer assembly 22 includes a web alignment andfeed station 22a and cooperative printer station 22b (FIGS. 1, 7 and 8).The chief components at the printing station include a web advancing andsupporting vacuum bed platen that reciprocates between stations 22a and22b, and the printing apparatus that includes a silk screen stencilframe 172 above the platen, and a transversely reciprocating squeegeesupporting carriage 174.

The vacuum bed platen 170 is slidably mounted on a fixed cylindricalguide shaft 178 (FIGS. 4 and 7) extending in the longitudinal directionof the web along the length of the back of the two stations. A slidebearing 180 encircles this rod and is fixedly attached along the rear ofplaten 170. The front edge portion of bed 170 has an attached followerroller 184 that rides on track 182 (FIG. 4). This track is affixed toframe member 184 along the front of the printing unit, parallel to shaft178. The platen reciprocates from an initial position at station 22a asshown by the dotted lines on the left hand side of FIG. 8 where registryis made with the web stock, to a second position at station 22b beneaththe squeegee assembly at the right hand side of the structure in FIGS. 7and 8, where the printing actually takes place. When the platen is instation 22a, registry is made with the web with vertically reciprocableindex pins that move with the platen, specifically by raising registerpins up through the end of the platen to fit into the three index holespreviously punched by means 20. These pins are tapered to assure initialinsertion into the holes, and have a diameter at the base of the pinsequal to that of the holes, to assure exact registry. The pins areshifted upwardly by the special mechanism shown must clearly in FIG. 9.That is, the lower ends of pins 190 are mounted on a plurality ofcantilever arms 194 (FIGS. 7 and 8) which in turn are mounted on theopposite ends thereof to transverse pivot shaft 196. The arms and pivotshaft are shifted to provide a vertical movement to pins 190 by verticalshifting of a depending leg 198 affixed to the front most one ofcantilever arms 194. At the lower end of leg 198 is a cam follower 200fitting within a pivotal cam track 202. This cam track in turn ismounted on a longitudinal pivot shaft 204, to which is also affixeddepending leg 206. A link 108 is pivotally connected to leg 206, and isoperably connected to the drive means so that, when it shiftslongitudinally in the direction indicated by the arrows in FIG. 9, itpivots the cam track 202, to vertically shift cam follower 200, leg 198,and thus elevate the alignment index pins. Link 208 is shifted by pivotlever 209 operated by a cam (not shown) on camshaft 356.

The mounting of the pins on pivotal cantilever arms causes them to movein a large radius arc toward the printing station, so that the insertedpins first draw the web tight, at which time punch 20 reciprocates toform the next set of index holes.

Immediately downstream and adjacent to the printing station 22b, andthus to platen 170 when under the printer, is a fixed vacuum bed 169(FIG. 6). It is hollow, is connected to a vacuum source, and hasorifices 167 to its upper surface. It is actuated after platen 170reaches the printing station, to help hold web W, and remains activatedafter the vacuum on platen 170 is released to allow the platen to bereturned to the alignment station 22a, to hold web W from reversing withthe platen.

A pair of web support cables 165 (FIG. 6), attached to bed 169, supportweb W from projecting between held 169 and platen 170 when the latter isspaced from the former. Cables 165 extend through passages in platen170.

In the operation of this apparatus, the pins are elevated after theplaten has reached the alignment station 22a, and are graduallyretracted as the platen moves toward the printing station, by shiftingthe cam track downwardly. I-Iollow platen 170 is evacuated through asuitable flexible hose connection (not shown) made to its underside, tohold a segment of web. The web is thus initially advanced by both thepin and hole connection and the platen pressure differential. The platenevacuation causes a pressure differential across the web portion due toa plurality of patterned vacuum orifices 210 (FIG. 6) which extendbetween the hollow interior of platen 170 and its upper surface. Oncethe web is in motion, the pins retract and the pressure differentialcontinues to advance it to the printing station. When the platen reachesprinting station 2212, so that it has carried a particular portion ofthe web into accurate registry therewith, the drive mechanism for thesqueegee apparatus goes into operation.

The advancement of platen 170 occurs simultaneously with advancement ofthe other printing unit employed by attaching sleeve 180 (FIG. 4) to areciprocating drive bar 181 with a clam 183. Bar 181 extends along thelength of the system and is reciprocated by a master rotationallypowered cam 187 (FIG. 1).

Referring now to the squeegee assembly (FIGS. 4 and 6), it includes ageneral support member 230 on the opposite ends of which are mounted apair of slide guides 232 which receive the squeegees in a manner to bedescribed hereinafter, and which are specially pivotally mounted to apair of carriage plates 234. To these carriage plates are mounted aplurality of rollers 240 on the forward ends of the carriages, and 240on the rearward ends. Attached to rollers 240 on opposite sides of theassembly is a first link 242, and connected thereto is a second link 244extending down to a fixed connection on pivot shaft 246 (FIG. 5). Alsoconnected fixedly to shaft 246 is a cantilever arm 248 which ispivotally secured to a tie rod 250 that has its lower end pivotallyconnected to a crank 252 mounted on drive shaft 254. This drive shaft isdriven by a belt and pulley connection 256 from motor 258. Thus,rotation of the drive assembly causes crank rotation, to reciprocate tierod 250, pivot lever 248, and hence reciprocate the squeegee assemblyalong a pair of cantilevered guide track units 270 transverse to thegeneral orientation of the web. In FIG. 6, the device is shown withsqueegee elements themselves removed so that the other members of theassembly can be more readily illustrated. Also, in FIG. 6 the stencilframe member 172 is removed. The printing stroke occurs during themovement of the squeegee assembly from the back initial positionillustrated in FIG. 6, through the printing step shown in FIG. 5, to theextended position. On its return stroke, the squeegee assembly iselevated above the sheet so it will not make contact with the stencilscreen. During the elevated return stroke however, a flow coater blade300 having a width equal to the width of the squeegee (FIG. 12) isallowed to drop to flood coat the excess ink back across stencil screen302 inside the stencil screen frame. The detailed structure andoperation of this flow coater and squeegee mechanism will be describedhereinafter.

The vertical shifting of the squeegee assembly is obtained by actuallyshifting its track assembly 270. More specifically, referring to FIGS. 4and 5, attached securely to the track assembly is a pair of verticallydepending supports 310 which are guided in their travel by cam followers312 and 314 and are partially biased to an upward position by tensionspring 316. The weight of the squeegee assembly end tracks causes thisstructure to normally remain in a lowered position, however, untilelevated by upward shifting of pivot lever 318 engaging a follower 320on the lower end of supports 310. Lever 318 is pivotally mounted to ashaft 322 on its opposite end, and pivotally connected to a lift member330, which is slidably mounted in guide 332, and includes a cam followerpin 334 on the upper end thereof. A rotational cam 336 mounted onrotational shaft 254 engages this follower to lift the entire mechanismon a controlled basis. This is arranged such that the squeegee assemblyis lowered only during the forward printing pass, and is elevated on thereturn stroke. The timing of this raising and lowering function issynchronized with the passage of the squeegee assembly since both aredriven from the same shaft 254.

It has also been found advisable to elevate the stencil screen byelevating its frame 172 temporarily after the printing stroke, while theweb is being advanced through the printing station. This is done bypushing the front of the stencil screen frame 172 up with a verticallyshiftable pin 342, to pivot it about its rear edge. This lifts the framefront ends up on its alignment pin 340. Push pin 342 is connected to abell crank 344 which is in turn pivotally operated by a link 346connected to a pivot link 350. This link 350 is pivotally mounted tosupport 352 and shifted by a rotational cam 354 on a timing cam shaft356. This same camshaft also controls the vacuum connection to movableplaten and to fixed holding platen 169 through cam operated valves (notshown).

The actual squeegee assembly has a special construction to allow rapidfiipover change between one squeegee and another while the unit is inoperation. This is important to this equipment since any shut down ofthe continuous process is detrimental to the entire operation. Thedevice has a spare squeegee unit which extends upwardly and afunctioning squeegee that extends downwardly. The spare squeegee can berotated to the downwardly oriented operative position between squeegeestrokes. Referring to FIGS. 10 and 11, each of the squeegees includes aflexible squeegee element and a support means therefor. That is, theoperating squeegee includes a holder 320 and a flexible element 322 topass along the surface of the screen. Likewise, the spare squeegee unitincludes a holder 320 and a flexible element 322'. Both are mounted on acommon support 328, which is mounted to a carriage. Each has alignmentstud members, 324 and 324' respectively, which extend into passages 326in fixed support member 328. All of these members slidably interfit inslide tracks 330 in spaced members 232. A pair pair of shoulder screws340 extending into both ends of unit 328 through respective orifices 321and 323 in plates 234 and element 232 to form pivot pins to enableelement 328 and thus elements 232 to be rotated thereon. Control of thisrotation is had by a pair of J-shaped detent members 350 and 350. Thesedetent members also serve a secondary function of locking the lowersqueegee means in its operative position to prevent it from falling outof the assembly and to release the spare, upper squeegee means forreplacement thereof. These detents project through slots 325 and 325 inmembers 232. Each of these generally J-shaped hook members has anelongated leg which projects into corresponding passages 352' and 352 insupport 328, with compression springs 354 and 354 in these passagesbiasing the detents to an outward extended position. A recess 356 isformed in the inside face of member 234 and aligned with the J-shapedmember which is associated with the upper squeegee unit to align theentire rotational mechanism into its intended operative verticalorientation. The detents also have short legs which can project intorecesses 360 and 360' in squeegee holders 320 and 320'. Projection ofdetent into recess 356 retracts its short leg from holder 320', torelease the upper squeegee element, enabling it to be removed andreplaced. The combination detent hook element 350 for the lower squeegeeassembly is held inwardly by the inside face of element 234 against itscompression spring to a position where its second leg is inserted intorecess 360, to hold the lower squeegee in a locked position preventingit from falling out. An L-shaped latch 355 (FIG. 17) is pivotallymounted in its center to member 234 and biased toward element 232 by atension spring 357 between latch 355 and track 270 to lock therotational squeegee assembly in aligned position. In order to shiftsqueegee 320 from its lowered position to an elevated position forreplacement therefor, it is only necessary to release latch 355, graspthe upper squeegee and forcibly rotate it, causing the rounded outer endof hook 350 to slide on the tapered surface of recess 356, and therebyto retract it from recess 356 against its compression spring, so thatthe device can be rotated 180 in a fraction of a second. By so doing,the lower J-shaped member 350 snaps into the recess to automaticallyalign the other lower squeegee in operative position, while enabling theupper squeegee to be removed and replaced, and the latch snaps back tolock position. Thus, there is no need to halt the entire web printingand drying process in order to replace Squeegees, since the unit can bequickly revolved between print strokes.

As mentioned previously, a flow coater assembly is also employed as at300 in FIG. 12. This transverse flow coater blade is mounted to asupport 400 which is free to float vertically in its slots 401 (FIGS. 6and 13), to ride under the bias of its own weight across the printscreen 302. It can be elevated by a T- shaped lifting link 404 which ispivotally mounted at 406, and projects beneath an extending shoulder 400of support 400. This link 404 can be shifted between stops 408 and 410(FIG. 12) by a linkage 414, 416.

SUPPLEMENTAL EQUIPMENT The slip coat applicator 30, laminator 32, crossslitter means 34, longitudinal slitter means 36, underside scoring means38, and cut off means 40, may optionally be used.

The slip coater 30 is intended to apply a protective coating over thesurface of the dry printed ink.

The laminator means 32 includes a main lamination roll support 500(FIG. 1) mounting a roll of an adhesively backed laminator material,normally transparent, which is also covered with a removable protectivesheet. Unwinding of the laminator roll stock is controlled by a suitablebrake 502. The laminating material 504 is applied to the printed surfaceof web W by pressure roll means 506, while the removable protectivesheet 507 is wound up on a roll support 508.

The cross slitter 34 is a transversely reciprocating mechanism withslitting devices 512 mounted thereon to slit the cover sheet or thecover sheet and web at spaced intervals.

The longitudinal slitting means 36 includes a plurality of transverselypositioning slitting elements 520 for cutting the laminator sheet 504 atspaced intervals.

The underside scoring means 38 includes a plurality of slitters 522 forscoring the printed web.

If desired the printed stock can be rolled up at the end of theoperation. Alternatively, it can be slit into separate printed sheets bycut off means 40 such as a vertically reciprocating blade unit.

OPERATION Basically, the operation of the system and each of itscooperative components can be understood from the previous descriptiongiven. In normal operation the web W extends the length of the system.Web W is pulled off the active roll 60 on roll support 12 by advancingvacuum tapes 63 and 65 until the slack web in chamber 16 shifts limitswitch 67 to shut off the advancing tapes. The web extends around thecurvilinear path of dryer 18, where the air flow is constant, andthrough punch means 20 to the first printing unit. It is advancedthrough these components by reciprocating vacuum platen 170 in printerunit 22. That is, with platen 170 in station 22a, index fingers rise onan arc into holes in web W to tighten the web and align it, while platen170 is evacuated, and punch 20 then forms the next set of index holes.Platen then advances with the web to the print station, as fingers lowerto miss the edge of stencil frame 172. With the platen beneath thestencil frame in print station 22b, bed 169 is evacuated to help holdthe web. The squeegee assembly is then lowered, and the squeegee isadvanced transversely across the stencil screen to print one color in apattern on the indexed web portion. The assembly then rises and returnsto its initial position, pulling the flow coater 300 back across thescreen. The vacuum in platen 170 then is released, while that in bed 169is held, and platen 170 is shifted back to station 22a. The printed webis then progressively pulled to and through dryer 24 by the next printer26, as printer 22 advances more slack from chamber 16. When the printedweb is advanced to the next printer, it is accurately registeredtherewith by the index pins in this next printer. Then the vacuum bed isadvances as with the first printer, so that when the web portion isprinted with another color in a selected pattern, exact registry withthe first ink pattern, now dried, occurs.

The web continues through the selected number of printers to the finaldryer, after which the web is optionally worked on with the supplementaldevices 30, 34, 36, 38 and 40.

In actual practice, the system has worked extremely well, enabling veryaccurate, high quality, multicolor print patterns to be automaticallyreproduced hour on end, at a cost which is only a fraction of thatnormally encountered.

The unique printers are completely reliable and accurate. Replacementsqueegees can be readily substituted between print strokes, so as to notrequire the system to be stopped.

The unique dryers are rapid, safe, reliable, and thorough, always givingcomplete web control, and completely cooperative with the printers forcontinuous operation.

It will be realized that the mechanical linkages and controls could bemodified in many ways to suit a particular job, within the conceptstaught herein. Hence, the invention is intended to be limited only bythe scope of the appended claims and the reasonably equivalents thereto.

I claim:

1. A screen printing system capable of repeat printings of multiplecolor patterns in registry on portions of a continuous web comprising:means to support a continuous web on a flow path; web punching means insaid flow path to punch holes in the web for creating index indicia atcontrolled intervals on the web; a plurality of screen printing unitsalong said flow path, downstream of said web punching means; webadvancing means associated with each of said screen printing units, saidweb advancing means including a web-supporting printing platen shiftablefrom a first position upstream of said printing unit to a secondposition aligned with said printing unit, said platen havingpressure-differential web-attraction means at is surface to shift theweb between said positions; web index register means at each of saidscreen printing units mounted for movement with said platen, said webindex register means including shiftable projection means oriented andreciprocable toward the web holes to interengage the holes; and means toreciprocate said projection means to cause momentary registry of eachweb portion with each printing unit for accurate printing.

2. The system in claim 1 wherein said web index register means ismounted to said platen to move therewith, and said means to reciprocatesaid projections is operably associated with said bed in a manner towithdraw said projections from the holes in the web as the web is beingadvanced by said platen to said second position.

1. A screen printing system capable of repeat printings of multiplecolor patterns in registry on portions of a continuous web comprising:means to support a continuous web on a flow path; web punching means insaid flow path to punch holes in the web for creating index indicia atcontrolled intervals on the web; a plurality of screen printing unitsalong said flow path, downstream of said web punching means; webadvancing means associated with each of said screen printing units, saidweb advancing means including a web-supporting printing platen shiftablefrom a first position upstream of said printing unit to a secondposition aligned with said printing unit, said platen havingpressure-differential web-attraction means at is surface to shift theweb between said positions; web index register means at each of saidscreen printing units mounted for movement with said platen, said webindex register means including shiftable projection means oriented andreciprocable toward the web holes to interengage the holes; and means toreciprocate said projection means to cause momentary registry of eachweb portion with each printing unit for accurate printing.
 2. The systemin claim 1 wherein said web index register means is mounted to saidplaten to move therewith, and said means to reciprocate said projectionsis operably associated with said bed in a manner to withdraw saidprojections from the holes in the web as the web is being advanced bysaid platen to said second position.